package com.example.ssm_demo1.Service;import com.example.ssm_demo1.entity.Userinfo;import com.example.ssm_demo1.mapper.UserMapper;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.stereotype.Service;@Servicepublic class UserService {    @Autowired    private UserMapper userMapper;    public Userinfo getUserById(Integer id)    {        return  userMapper.getUserById(id);    }}